Is there a way to save a Dataset natively, without polygon conversions?

[thomasf1]

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Question

Is there a way to save a Dataset natively, without polygon conversions? Would be great If there would be a way to save the dataset with the masks as a zip, all save formats (coco, yolo, voc) do some processing. Ideally there would be a way to natively save a dataset (maybe as a ZIP file).

My usecase is experimenting to get the polygon conversion when saving as yolo after a run just right and writing some custom code for it, so it would be helpful to have the "raw" state with the masks saved somewhere.

Additional

I might just have overlooked some obvious way of saving the dataset... Otherwise it is a feature request I guess.

[github-actions]

Hello there, thank you for opening an Issue ! 🙏🏻 The team was notified and they will get back to you asap.

[SkalskiP]

Hi, @thomasf1 👋🏻 Sounds interesting. Have you perhaps already thought about the structure of such a dataset? Would each mask be stored as a separate black-and-white photo? How would you store information about the class to which an object with a given mask belongs?

[thomasf1]

Well, there is already a standard/solution for coco that´s somehow not being used by roboflow: RLE (_frString)

Also, not supporting masks causes other issues: When converting to Polygons, cutouts in masks seem often to be converted as a separate polygon.

Example: A person having this arms on his hips. The triangle shape inside the arms isn´t part of the person, but surrounded by it. The way supervisions translates that into polygons is as follows:

• The outer shape of the person as a person polygon (reasonable, expected behaviour)
• The inner cutout of background as another person polygon (blatantly wrong and counterproductive)

(not sure if that qualifies as a BUG or is somehow intended behaviour?)

[thomasf1]

@SkalskiP There is some code here that should get you far: https://github.com/waspinator/pycococreator/blob/master/pycococreatortools/pycococreatortools.py

Also, in binary_mask_to_polygon, they seem to add some padding to avoid a problem supervision (and the roboflow app smart polygon) has: Creating polygons that reach to the image edges. Unfortunately, most polygons leave a 1+ px gap from the edge of the image when the masked subject goes beyond the edge of the image.

[thomasf1]

In an Ideal world, both roboflow.com and supervision would use both masks and polygons and decide intelligently which one to use.

For instance segmentation:
Masks for:

• Objects with cutouts
• Objects that are overlapped by something else, cutting the mask into separate areas that are not connected (which in polygons results in several polygons, loosing the information that they are part of one Object)
• Maybe very small Objects

Polygons for everything else (maybe configureable)

[thomasf1]

@SkalskiP What do you think?

[SkalskiP]

@thomasf1 agree! Expanding COCO annotations format support is the easiest way to unlock that capability.

[thomasf1]

Would you need any help with it?

[MihaiDavid05]

Well, there is already a standard/solution for coco that´s somehow not being used by roboflow: RLE (_frString)

Also, not supporting masks causes other issues: When converting to Polygons, cutouts in masks seem often to be converted as a separate polygon.

Example: A person having this arms on his hips. The triangle shape inside the arms isn´t part of the person, but surrounded by it. The way supervisions translates that into polygons is as follows:

• The outer shape of the person as a person polygon (reasonable, expected behaviour)
• The inner cutout of background as another person polygon (blatantly wrong and counterproductive)

(not sure if that qualifies as a BUG or is somehow intended behaviour?)

In an Ideal world, both roboflow.com and supervision would use both masks and polygons and decide intelligently which one to use.

For instance segmentation: Masks for:

• Objects with cutouts
• Objects that are overlapped by something else, cutting the mask into separate areas that are not connected (which in polygons results in several polygons, loosing the information that they are part of one Object)
• Maybe very small Objects

Polygons for everything else (maybe configureable)

@thomasf1 I opened an issue specifically for this hole preservation matter. I also built an exporter that deals with almost everything that you said above, You can find it here.